The present invention relates to a positioning mechanism.
More particularly this invention concerns a positioning mechanism useable in an automotive vehicle for displacing a window, seat or the like.
An automotive vehicle is frequently equipped with at least one positioning mechanism which comprises a pinion rotatably mounted on a support and meshing with a rack formed on a lever also pivoted on the support. Normally the pinion is connected to a lever or handle so that the user can rotate it and thereby pivot the lever. Such an arrangement can be used to raise or lower the vehicle window, or to raise or lower the vehicle seat. The movable load normally is connected to the pivotal lever.
It is essential that this mechanism be extremely robust so as to withstand the long-term service that is required of it in an automotive vehicle. Furthermore, since the vehicle incorporating such mechanism must be produced at the lowest possible cost, it must be possible to mass-produce the mechanism at the lower possible expense. Finally, the mechanism must operate as smoothly as possible in order to allow the load spring positioned by the mechanism to be moved with relative ease.
Thus the disadvantages of the known systems fall into two main groups. On the one hand the positioning mechanism is made with a great deal of care, normally involving machining of the various elements for a tight fit, so that it is relatively expensive but gives a long service life and operates easily. On the other hand, when stamp gears or the like are used the play between them, which must be left in order to compensate for manufacturing tolerances, frequently is such that slip between the parts of the mechanism is possible. Thus although the rack on the lever may mesh perfectly with the pinion in one angular position of the lever, when displaced somewhat it meshes less well so that slippage can occur. Today it therefore seems virtually impossible to provide a positioning mechanism which both functions surely and easily, but which can be produced at a low cost.